A Cisco Catalyst switch receives an ingress Ethernet frame on interface GigabitEthernet0/1 assigned to VLAN 10. The frame contains a source MAC address that does not currently exist in the MAC address table and a destination MAC address that is already registered on interface GigabitEthernet0/2 in VLAN 10. Arrange the switch processing actions in the correct chronological sequence from initial frame reception to egress forwarding.
- 1The switch receives the Ethernet frame on interface GigabitEthernet0/1 and parses the Layer 2 header for source MAC, destination MAC, and VLAN membership.
- 2The switch updates the VLAN 10 MAC address table by creating a dynamic entry that binds the unknown source MAC address to interface GigabitEthernet0/1.
- 3The switch performs a MAC address table lookup for the frame's destination MAC address within the scope of VLAN 10.
- 4The switch identifies the existing entry for GigabitEthernet0/2 and forwards the unicast frame out interface GigabitEthernet0/2.
Answer
The correct sequence is: (1) Frame reception and header parsing on GigabitEthernet0/1, (2) Learning the source MAC address by adding an entry for GigabitEthernet0/1 in VLAN 10, (3) Looking up the destination MAC address in the MAC address table, and (4) Forwarding the unicast frame out GigabitEthernet0/2.
When a switch receives a frame, it follows a strict sequence of operations: first receiving and parsing the header, then learning the source MAC address (adding/updating the MAC table entry for the ingress port), looking up the destination MAC address in the table, and finally forwarding the frame out the designated destination interface.
Step-by-Step Solution
Key Concept
Layer 2 Switch Ingress Processing & MAC Address Table Operation